Methods for treating immunodeficiency disease

ABSTRACT

The present invention relates to methods of treating patients with WHIM syndrome or related disorders, such as myelokathexis, in which X4P-001 is administered in order to reduce the activity of CXCR4. The methods demonstrate surprising effectiveness, with comparatively little toxicity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application serial numbers U.S. Ser. No. 62/271,087, filed Dec.22, 2015, and U.S. Ser. No. 62/428,964, filed Dec. 1, 2016, the entiretyof each of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to methods for treating immunodeficiencydisease, in particular, methods for treating warts,hypogammaglobulinemia, immunodeficiency, myelokathexis (WHIM) syndrome,or “WHIMS.” WHIMS is a disease characterized by neutropenia andlymphopenia resulting in skin and genital warts and recurringinfections.

BACKGROUND OF THE INVENTION

WHIM syndrome is a rare autosomal dominant immunodeficiency disorderwhich results in multiple mutations that remove 10-19 amino acids fromthe carboxy-terminus of CXCR4, a chemokine receptor expressed by bothhematopoietic and non-hematopoietic cells [Hernandez 2003]. The mutationin the CXCR4 receptor is known to prevent the normal release of matureneutrophils from the bone marrow to the blood [Kawai 2005] resulting inneutropenia in patients with WHIM syndrome [Dale 2011]. In addition toneutropenia, WHIM syndrome is characterized by lymphopenia that affectsthe levels of circulating T and B cells. [Balabanian 2012, Dotta 2011]resulting in low levels of immunoglobulins. The exact mechanism forlymphopenia is not known but may be attributable to interruption of thenormal trafficking of lymphocytes and their retention in the marrow andother lymphoid tissues [Ma 1999].

Generally, clinical symptoms first appear in early childhood withrecurrent bacterial infections due to low levels of white blood cellsand antibodies [NORD 2015]. Common infections include otitis media,cellulitis, impetigo, abscess, bacterial pneumonia, sinusitis, andperiodontitis. Affected individuals are particularly susceptible tohuman papillomavirus (HPV), which can cause widespread warts affectingthe hands, feet, face, and trunk and are often recalcitrant [NORD 2015].Mucosal and genital warts may also develop and these warts areassociated with an increased risk of progressing to cervical carcinoma[NORD 2015]. Current treatments include G-CSF and intravenousimmunoglobulin but these are non-specific, expensive, difficult toadminister, and only partially effective [Kawai 2009].

Present treatments available for patients with WHIM syndrome areinsufficient. There is a clear unmet need for agents that improveoutcomes in the treatment of such patients.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates X4P-001 inhibition on SDF-1α binding toCXCR4+CEM-CCRF cells.

FIG. 2 illustrates X4P-001 inhibition of SDF-1α stimulated Eu-GTPbinding.

FIG. 3 illustrates X4P-001 inhibition of SDF-1α stimulated [³⁵S]-GTP-γ-Sbinding.

FIG. 4 illustrates X4P-001 inhibition of SDF-1α induced calcium flux.

FIG. 5 illustrates X4P-001 inhibition of SDF-1α stimulated CCRF-CEMchemotaxis.

FIG. 6 illustrates SDF-1α stimulation of calcium flux in wild-type andCXCR4 variants.

FIG. 7 illustrates X4P-001 inhibition of SDF-1α stimulation in wild-typeand CXCR4 variants.

FIG. 8 illustrates white blood cell (A), neutrophil (B), and lymphocyte(C) counts following oral administration of X4P-001 to male beagle dogs.

FIG. 9 illustrates dose-dependent increases (2-3×) in WBC counts inhuman subjects who were administered X4P-001.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

Effective targeted treatments for WHIM syndrome, like X4P-001, areneeded for the management of patients. X4P-001 can be administeredorally, which in addition to being a targeted treatment, makes it anexcellent candidate in a chronic treatment setting that would berequired for patients with WHIM syndrome.

The ligand for the CXCR4 receptor is SDF-1α which is involved withnumerous physiologic processes and plays a central role in hematopoieiccells homing to and being released from the bone marrow [Lapidot 2002].Mutations in the CXCR4 prevent the normal release of mature neutrophilsfrom the bone marrow into the blood [Kawai 2005]. Bone marrowexaminations of patients affected with WHIM syndrome show abundantneutrophils with hyper-segmented nuclei and remnants of neutrophils inbone marrow macrophages. [Bohinjec 1981].

The disruption of the CXCR4/SDF-1α axis results in WHIM syndromepatients having low white blood cell counts usually <1.0×10⁹/L withsevere neutropenia and lymphopenia present [Dale 2011]. The mechanism ofCXCR4/SDF-1α axis disruption is described in the following paragraph.

CXCR4 is a G protein-coupled receptor and engagement by SDF-1α inducestypical activation of G protein—dependent pathways of a chemokinereceptor [Baggiolini 1998, Zlotnik 2000]. These processes are regulatedin a timely manner by the recruitment of β-arrestin to the receptor thatprecludes further G-protein activation (ie, desensitization) and leadsto receptor internalization. Mutants of CXCR4 associated with WHIMsyndrome give rise to impaired desensitization and internalization ofthe receptor upon SDF-1α exposure, leading to enhanced and prolongedreceptor activation. [Hernandez 2003, Balabanian 2005, Gulino 2004,Kawai 2005, Lagane 2008, McCormick 2009]. Because CXCR4 normallyregulates leukocyte trafficking and in particular is important forneutrophil adhesion in the bone marrow, prolonging the activity ofSDF-1α dependent signaling is the probable cause for myelokathexis (MKX)and neutropenia seen in WHIM syndrome. [McDermott 2011-a].

X4P-001 is a small molecule antagonist of CXCR4 having the potential toblock the enhanced signaling activity of mutant CXCR4 resulting in anincrease in the number of circulating white blood cells by overcomingthe impaired down regulation (receptor internalization) and receptordysfunction caused by mutant CXCR4 (McDermott 2011-b). It has also beendemonstrated that X4P-001 inhibits the most common genotypic forms ofCXCR4 attributable to WHIM syndrome (R334X and E343X) to a similarextent as the wild type CXCR4 [Mosi 2012].

These studies demonstrated that oral administration of up to 400 mg BIDfor 3.5 days (healthy volunteers) and 200 mg BID for 8-10 days (healthyvolunteers and HIV patients) was well-tolerated with no pattern ofadverse events or clinically significant laboratory changes. Thesestudies also demonstrated pharmacodynamic activity, with dose- andconcentration-related changes in circulating white blood cells (WBCs);and a high volume of distribution (VL), suggesting high tissuepenetrance.

The inventors conceived that CXCR4 antagonism by X4P-001 may providesignificant treatment benefits in patients with WHIMS, and individualaspects of WHIMS, which is an acronym for warts, hypogammaglobulinemia(low immunoglobulin levels), immunodeficiency (susceptibility toinfections) and myelokathexis (trapping of white blood cells in the bonemarrow). Administration of X4P-001 inhibits SDF-1α binding to CXCR4 andCXCR4+CEM-CCRF cells. [See FIG. 1]. Administration of X4P-001 alsoinhibits CXCR4 cell signaling and SDF-1α induced calcium flux. [SeeFIGS. 2-4]. In this manner, X4P-001 inhibits SDF-1α stimulated CCRF-CEMchemotaxis. [See FIG. 5].

Moreover, the inventors conceived that such a result might be achievedwith comparatively little toxicity since CXCR4-targeted drugs arespecifically targeted and do not induce cell cycle arrest in normalproliferating cell populations. Accordingly, the present inventionprovides significant advantages in treatment outcomes utilizing the lowtoxicity and effects of the CXCR4 inhibitor AMD11070 (X4P-001).

In the present invention, patients with WHIMS, or related syndromes, aretreated with X4P-001, or a pharmaceutically acceptable salt orcomposition thereof either as a single agent (monotherapy), or incombination with another agent, such as granulocyte colony-stimulatingfactor (G-CSF), granulocyte-macrophage colony-stimulating factor(GM-CSF) or intravenous immunoglobulin (IVIG).

In some embodiments, the present invention provides a method fortreating WHIMS in a patient in need thereof, wherein said methodcomprises administering to said patient X4P-001 or a pharmaceuticallyacceptable salt or composition thereof in combination with G-CSF, GM-CSFand/or IVIG. Other treatments that may be utilized in the treatment ofWHIMS include bone marrow transplantation and treatment with cord bloodstem cells.

In some embodiments, a provided method comprises administering theX4P-001, or a pharmaceutically acceptable salt or composition thereof,to a patient in a fasted state.

In certain embodiments, the present invention provides a method fortreating WHIMS in a patient in need thereof, wherein said methodcomprises administering to said patient X4P-001, or a pharmaceuticallyacceptable salt or composition thereof, further comprising the step ofobtaining a biological sample from the patient and measuring the amountof a disease-related biomarker. In some embodiments, the biologicalsample is a blood sample. In certain embodiments, the disease-relatedbiomarker is selected from the group consisting of CXCR4, SDF-1α/CXCL12;and GRK3 (G protein coupled receptor kinase 3).

In certain embodiments, the present invention provides a method fortreating WHIMS in a patient in need thereof, wherein said methodcomprises administering to said patient X4P-001 or a pharmaceuticallyacceptable salt or composition thereof.

In some embodiments, the X4P-001 or a pharmaceutically acceptable saltthereof is administered in a dose of from about 25 mg/day to about 150mg/day.

In some embodiments, said patient exhibits warts.

In some embodiments, cells taken from the patient exhibit expression ofa mutant form of CXCR4.

In some embodiments, cells taken from the patient exhibit increasedexpression of CXCR4.

In some embodiments, the method further comprises the step of obtaininga biological sample from the patient and measuring the amount of adisease-related biomarker.

In some embodiments, the biological sample is a blood sample.

In some embodiments, the disease-related biomarker is circulating CXCR4.

In some embodiments, the X4P-001 or a pharmaceutically acceptable saltor composition thereof is administered orally once per day.

In some embodiments, the X4P-001 or a pharmaceutically acceptable saltor composition thereof is administered orally twice per day.

In some embodiments, the present invention provides a unit dosage formcomprising a composition comprising:

-   -   (a) X4P-001, or a pharmaceutically acceptable salt thereof—about        10-20% by weight of the composition;    -   (b) microcrystalline cellulose—about 70-85% by weight of the        composition;    -   (d) croscarmellose sodium—about 5-10% by weight of the        composition;    -   (e) sodium stearyl fumarate—about 0.5-2% by weight of the        composition; and    -   (f) colloidal silicon dioxide—about 0.1-1.0% by weight of the        composition.

In some embodiments, the unit dosage form is in capsule form.

In some embodiments, the capsule comprises about 25 mg X4P-001, or apharmaceutically acceptable salt thereof.

In some embodiments, the present invention provides a method fortreating WHIM syndrome in a patient in need thereof, comprising the stepof administering to the patient a disclosed unit dosage form.

In some embodiments, the present invention provides a method fortreating WHIM syndrome in a patient in need thereof, comprisingadministering to said patient X4P-001 or a pharmaceutically acceptablesalt or composition thereof, in an amount effective to increase absoluteneutrophil count (ANC) and/or to increase absolute lymphocyte count(ALC) in the patient, for example in the patient's blood. In someembodiments, the ANC and/or ALC is increased in the patient to about60%, 70%, 80%, 90%, 95%, or 100% of that of an average, healthy humanwho does not have WHIM syndrome or another immunodeficiency. In someembodiments, the ANC and/or ALC is increased in the patient to about60%, 70%, 80%, 90%, 95%, or 100% of that of an average, healthy human ofsimilar age, weight, and sex to that of the patient.

In some embodiments, the present invention provides a method fortreating WHIM syndrome in a patient in need thereof, comprisingadministering to said patient X4P-001 or a pharmaceutically acceptablesalt or composition thereof, in an amount effective to increase absoluteneutrophil count (ANC) to a level greater than or equal to 600/μL and/orto increase absolute lymphocyte count (ALC) to a level greater than orequal to 1000/μL.

In some embodiments, said patient originally exhibited ANC less than600/μL and/or ALC less than 1000/μL before treatment with X4P-001.

In some embodiments, said patient originally exhibited ANC less than400/μL and/or ALC less than 650/μL before treatment with X4P-001.

In some embodiments, a disclosed method results in increases in ANClevels to at least about 600/μL, about 800/μL, about 1000/μL, about1,200/μL, or to about that of a human with a normally-functioning immunesystem, on at least 85% of assessments.

In some embodiments, a disclosed method results in increases in ALC toat least about 1000/μL, about 1,200/μL, or about 1,500/μL, or to aboutthat of a human with a normally-functioning immune system, on at least85% of assessments.

In some embodiments, a disclosed method results in improved levels ofprotective antibody in the patient in response to a vaccine.

In some embodiments, a disclosed method results in a lowered frequencyof infections in the patient, such as at least 50% less infections, suchas respiratory tract infections.

In some embodiments, a disclosed method results in increased levels oftotal circulating WBC, neutrophils, and/or lymphocytes. In someembodiments, cell counts of WBC, neutrophils, and/or lymphocytesincrease to at least 1.4× baseline. In some embodiments, cell counts ofWBC, neutrophils, and/or lymphocytes increase to at least 1.8× baseline.In some embodiments, cell counts of WBC, neutrophils, and/or lymphocytesincrease to at least 2.9× baseline. In some embodiments, cell counts oflymphocytes increase to at least 2.9× baseline. In some embodiments,cell counts of neutrophils increase to at least 2.7× baseline andlymphocytes to 1.9× baseline.

In some embodiments, the present invention provides a method of treatingWHIMS in a patient in need thereof, wherein said method comprisesadministering to said patient an effective amount of X4P-001 or apharmaceutically acceptable salt or composition thereof in conjunctionwith another treatment for warts, HPV infection, or neutropenia.

Dosage and Formulations

X4P-001 is a CXCR4 antagonist, with molecular formula C₂₁H₂₇N₅;molecular Weight 349.48 amu; appearance white to pale yellow solid;solubility: X4P-001 is freely soluble in the pH range 3.0 to 8.0 (>100mg/mL), sparingly soluble at pH 9.0 (10.7 mg/mL) and slightly soluble atpH 10.0 (2.0 mg/mL). X4P-001 is only slightly soluble in water; andmelting point of 108.9° ΔC.

The chemical structure of X4P-001 is depicted below.

In certain embodiments, the composition containing X4P-001 isadministered orally, in an amount from about 10 mg to about 600 mgdaily. In certain embodiments, the dosage composition may be providedtwice a day in divided dosage, approximately 12 hours apart. In otherembodiments, the dosage composition may be provided once daily. Theterminal half-life of X4P-001 has been generally determined to bebetween about 12 to about 24 hours, or approximately 14.5 hrs. Dosagefor oral administration may be from about 10 mg to about 300 mg once ortwice per day. In certain embodiments, the dosage of X4P-0001 useful inthe invention is from about 20 mg to about 600 mg daily. In otherembodiments, the dosage of X4P-001 useful in the invention may rangefrom about 25 mg to about 200 mg daily, from about 25 mg to about 150 mgdaily, from about 25 mg to about 100 mg daily, from about 25 mg to about50 mg daily, from about 50 mg to about 150 mg daily, or from about 50 mgto about 100 mg daily.

In some embodiments, a provided method comprises administering to thepatient a pharmaceutically acceptable composition comprising X4P-001wherein the composition is formulated for oral administration. Incertain embodiments, the composition is formulated for oraladministration in the form of a tablet or a capsule. In someembodiments, the composition comprising X4P-001 is formulated for oraladministration in the form of a capsule.

In certain embodiments, a provided method comprises administering to thepatient one or more capsules comprising 10 mg to 1200 mg X4P-001 activeingredient; and one or more pharmaceutically acceptable excipients. Incertain embodiments, the capsule is comprised of hard gelatin.

In certain embodiments, the present invention provides a compositioncomprising X4P-001, or a pharmaceutically acceptable salt thereof, oneor more diluents, a disintegrant, a lubricant, a flow aid, and a wettingagent. In some embodiments, the present invention provides a compositioncomprising 10 mg to 1200 mg X4P-001, or a pharmaceutically acceptablesalt thereof, microcrystalline cellulose, dibasic calcium phosphatedihydrate, croscarmellose sodium, sodium stearyl fumarate, colloidalsilicon dioxide, and sodium lauryl sulfate. In some embodiments, thepresent invention provides a unit dosage form wherein said unit dosageform comprises a composition comprising 10-200 mg X4P-001, or apharmaceutically acceptable salt thereof, microcrystalline cellulose,dibasic calcium phosphate dihydrate, croscarmellose sodium, sodiumstearyl fumarate, colloidal silicon dioxide, and sodium lauryl sulfate.In certain embodiments, the present invention provides a unit dosageform comprising a composition comprising X4P-001, or a pharmaceuticallyacceptable salt thereof, present in an amount of about 10 mg, about 20mg, about 25 mg, about 50 mg, about 75 mg, about 100 mg, about 150 mg,about 200 mg, about 250 mg, about 300 mg, about 400 mg, about 450 mg,about 500 mg, about 600 mg, about 700 mg, about 750 mg, about 800 mg,about 900 mg, about 1000 mg, about 1100 mg, or about 1200 mg. In someembodiments, a provided composition (or unit dosage form) isadministered to the patient once per day, twice per day, three times perday, or four times per day. In some embodiments, a provided composition(or unit dosage form) is administered to the patient once per day ortwice per day.

In some embodiments, the present invention provides a unit dosage formcomprising a composition comprising:

-   -   (a) X4P-001, or a pharmaceutically acceptable salt thereof—about        10-30% by weight of the composition;    -   (b) microcrystalline cellulose—about 60-80% by weight of the        composition;    -   (c) croscarmellose sodium—about 5-10% by weight of the        composition;    -   (d) sodium stearyl fumarate—about 0.5-2% by weight of the        composition; and    -   (e) colloidal silicon dioxide—about 0.1-1.0% by weight of the        composition.

In some embodiments, the present invention provides a unit dosage formcomprising a composition comprising:

-   -   (a) X4P-001, or a pharmaceutically acceptable salt thereof—about        14.7% by weight of the composition;    -   (b) microcrystalline cellulose—about 78.1% by weight of the        composition;    -   (c) croscarmellose sodium—about 6.0% by weight of the        composition;    -   (d) sodium stearyl fumarate—about 1.0% by weight of the        composition; and    -   (e) colloidal silicon dioxide—about 0.2% by weight of the        composition.

In some embodiments, the present invention provides a unit dosage formcomprising a composition comprising:

-   -   (a) X4P-001, or a pharmaceutically acceptable salt thereof—about        10-20% by weight of the composition;    -   (b) microcrystalline cellulose—about 25-40% by weight of the        composition;    -   (c) dibasic calcium phosphate dihydrate—about 35-55% by weight        of the composition;    -   (d) croscarmellose sodium—about 4-15% by weight of the        composition;    -   (e) sodium stearyl fumarate—about 0.3-2% by weight of the        composition;    -   (f) colloidal silicon dioxide—about 0.1-1.5% by weight of the        composition; and    -   (g) sodium lauryl sulfate—about 0.1-1.5% by weight of the        composition.

In some embodiments, the present invention provides a unit dosage formcomprising a composition comprising:

-   -   (a) X4P-001, or a pharmaceutically acceptable salt thereof—about        12.85% by weight of the composition;    -   (b) microcrystalline cellulose—about 31.92% by weight of the        composition;    -   (c) dibasic calcium phosphate dihydrate—about 44.4% by weight of        the composition;    -   (d) croscarmellose sodium—about 8.33% by weight of the        composition;    -   (e) sodium stearyl fumarate—about 1.38% by weight of the        composition;    -   (f) colloidal silicon dioxide—about 0.42% by weight of the        composition; and    -   (g) sodium lauryl sulfate—about 0.7% by weight of the        composition.

Inasmuch as it may be desirable to administer a combination of activecompounds, for example, for the purpose of treating a particular diseaseor condition, it is within the scope of the present invention that twoor more pharmaceutical compositions, at least one of which contains acompound in accordance with the invention, may conveniently be combinedin the form of a kit suitable for co-administration of the compositions.Thus the kit of the invention includes two or more separatepharmaceutical compositions, at least one of which contains a compoundof the invention, and means for separately retaining said compositions,such as a container, divided bottle, or divided foil packet. An exampleof such a kit is the familiar blister pack used for the packaging oftablets, capsules and the like.

The kit of the invention is particularly suitable for administeringdifferent dosage forms, for example, oral and parenteral, foradministering the separate compositions at different dosage intervals,or for titrating the separate compositions against one another. Toassist compliance, the kit typically includes directions foradministration and may be provided with a memory aid.

The examples below explain the invention in more detail. The followingpreparations and examples are given to enable those skilled in the artto more clearly understand and to practice the present invention. Thepresent invention, however, is not limited in scope by the exemplifiedembodiments, which are intended as illustrations of single aspects ofthe invention only, and methods which are functionally equivalent arewithin the scope of the invention. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description and accompanyingdrawings. Such modifications are intended to fall within the scope ofthe appended claims.

The contents of each document cited in the specification are hereinincorporated by reference in their entireties.

EXEMPLIFICATION Example 1: Non-Clinical Evaluation of X4P-001 Effects onCXCR4 In Vitro Pharmacology

The in-vitro pharmacology of X4P-001 (formally designated AMD11070) wasextensively studied and the results reported [Mosi 2012]. Presentedbelow is the relevant information from the Mosi 2012 literaturepublication. The SDF-1α isoform was used for the experiments describedbelow.

X4P-001 Inhibition of SDF-1α Binding to CXCR4

X4P-001 was shown to inhibit binding of [¹²⁵I]-SDF-1α to CCRF-CEM cells(T-lymphoblastoid cell line which naturally express CXCR4 [Crump 1997])in a heterologous competition binding assay. The results of the assayare shown in FIG. 2 below. The data was fitted to a single site bindingmodel and gave an IC₅₀ of 12.5±1.3 nM.

X4P-001 Inhibition of CXCR4 Cell Signaling

CXCR4 is a G-protein coupled receptor [Baggiolini 1998, Zlotnik 2000].As such the activation of the receptor can be measured using anonhydrolysable analogue of GTP such as fluorescently labeledEuropium-GTP (Eu-GTP) or radio labeled [³⁵S]-GTPγS. The results shown inFIG. 3 and FIG. 4 showed that X4P-001 inhibited CXCR4 activation withIC₅₀ values of 39.8±2.5 nM and 19.0±4.1 nM in the Eu-GTP binding and[³⁵S]-GTPγS assays, respectively.

Upon activation of a G-protein coupled receptor, intracellular signalingpathways are triggered resulting in the release of calcium fromintracellular stores. This calcium flux can be assayed using acalcium-chelating molecule, Fluo-4, which fluoresces upon bindingcalcium. X4P-001 was able to inhibit SDF-1α (2.5 nM SDF-1α) mediatedcalcium flux in CCRF-CEM cells with an IC₅₀ of 9.0±2.0 nM. The result isshown in FIG. 5.

A key property of all chemokines is that they induce a chemotacticresponse to a chemokine concentration gradient. X4P-001 was able toinhibit SDF-1α mediated chemotaxis of CCRF-CEM cells with an IC₅₀ of19.0±4.0 nM as shown in FIG. 6.

A summary of the above in vitro results is presented in Table 1 below:

TABLE 1 In Vitro Concentrations of X4P-001(IC₅₀) Associated withDifferent Biological Responses Response IC₅₀ (nM)^(a) Ligand Binding12.5 ± 1.3 Eu-GTP 39.8 ± 2.5 [³⁵S]-GTP 19.0 ± 4.1 Calcium Flux  9.0 ±2.0 Chemotaxis 19.0 ± 4.0 Average IC₅₀ 21.5 ^(a)= Results are expressedas mean ± SE

X4P-001 Selectivity for CXCR4

In order to demonstrate the specificity of X4P-001 for CXCR4 it wastested in calcium signaling assays against a panel of chemokinereceptors, and in ligand binding assays for BLT₁, the receptor forleukotriene B4 (LTB₄), and CXCR7. LTB₄ is a potent chemoattractant andits receptor is a G-protein coupled receptor. The results in Table 2show that the IC₅₀ of X4P-001 against CCR1, CCR2b, CCR4, CCR5, CCR7,CXCR3, and LTB₄ was >50 mM in all cases. X4P-001 did not inhibit SDF-1αbinding to CXCR7 at a concentration of 10 mM, the maximum concentrationtested in this assay. Together these data indicate that X4P-001 is aselective inhibitor of CXCR4.

In order to demonstrate the specificity of X4P-001 for CXCR4 it wastested in calcium signaling assays against a panel of chemokinereceptors, and in ligand binding assays for BLT₁, the receptor forleukotriene B4 (LTB₄), and CXCR7. LTB₄ is a potent chemoattractant andits receptor is a G-protein coupled receptor. The results in Table 2show that the IC₅₀ of X4P-001 against CCR1, CCR2b, CCR4, CCR5, CCR7,CXCR3, and LTB₄ was >50 mM in all cases. X4P-001 did not inhibit SDF-1αbinding to CXCR7 at a concentration of 10 mM, the maximum concentrationtested in this assay. Together these data indicate that X4P-001 is aselective inhibitor of CXCR4.

TABLE 2 Calcium Flux Response for Cell Lines Treated with X4P-001 forIC₅₀ Determination IC₅₀AMD11070 Receptor Cell line Ligand (μM) CCR1HEK293F-CCR1 MIP-1α/CCL3 >50 CCR2b HEK293F-CCR2b MCP-1/CCL2 >50 CXCR3HEK293F-CXCR3- IP-10/CXCL10 >50 Gαq15 CXCR7 Cf2Th.CXCR7SDF-1α/CXCL12 >10 CCR4 HEK293F-CCR4- TARC/CCL17 >50 Gαq15 CCR5HEK293F-CCR5 RANTES/CCL5 >50 CCR7 CCRF-CEM MIP-3β/CCL19 >50 BLT₁CHO-S-LTB₄ LTB₄ >50

X4P-001 Inhibition of C-terminal Variants of CXCR4

From a therapeutic perspective it is important that CXCR4 antagonistscan act on CXCR4 variants. Carboxy-terminal truncated variants of CXCR4have been reported associated with WHIM syndrome; nonsense mutationsresulting in a 19 amino acid truncation (R334X), and a 10 amino acidtruncation (E343X) and a frameshift mutation resulting in a 13 aminoacid truncation (S339fs342X) [Hernandez 2003, Kawai 2009]. The R334X andE343X CXCR4 variants were cloned and transiently expressed in the caninethymus cell line Cf2Th. This cell line was chosen due to its lack ofexpression of CXCR4 [Wong 2008]. Wild type CXCR4 was similarlysub-cloned into this cell line for control studies. In control studiesit was demonstrated that both these carboxy-terminal truncated variantswere able to respond to SDF-1α in the calcium flux assay with a similarpotency to wild type CXCR4. The EC₅₀ values for SDF-1α were 13.6, 11.3and 15.3 nM against the wild type, R334X and E343X variants of CXCR4,respectively (FIG. 6). The inhibitory effect of X4P-001 onSDF-1α-mediated calcium flux was assessed for the two CXCR4 variants.Both variants were inhibited to a similar extent as the wild type CXCR4with IC₅₀ values of 3.1, 8.5 and 4.6 nM for the wild type, R334X andE343X variants respectively (FIG. 7).

Discussion and Conclusions from In Vitro Studies

Using the CCRF-CEM cell line, which naturally expresses CXCR4 [Crump1997] it was shown that X4P-001 inhibits SDF-1α ligand binding to CXCR4with an IC₅₀ of 12.5±1.3 nM. X4P-001 also inhibited CXCR4 activation andsignaling as shown by inhibition of SDF-1α mediated G-protein activationof the CXCR4 receptor in two assays using either the fluorescent Eu-GTPor the radiolabeled [³⁵S]-GTPγS binding assays with IC₅₀ values of39.8±2.5 nM and 19.0±4.1 nM, respectively, and inhibition of SDF-1αmediated calcium flux with an IC₅₀ of 9.0±2.0 nM. X4P-001 also inhibitedSDF-1α-mediated chemotaxis, a CXCR4-mediated physiological response,with an IC₅₀ of 19.0±4.0 nM. In addition, X4P-001 had little or noinhibitory effect on either MIP1α, MCP-1, TARC, RANTES, MIP-3β, or IP10mediated calcium flux, ligands for CCR1, CCR2b, CCR4, CCR5, CCR7 andCXCR3, respectively, or SDF-1α binding to CXCR7, or LTB4 binding toBLT1, an alternative G-protein coupled receptor that mediateschemotaxis. These data indicate that X4P-001 is a selective inhibitor ofCXCR4 over the other chemokine receptors evaluated.

Mutations in CXCR4 resulting in truncation of the intracellularcarboxy-terminus of the receptor have been linked to the rare condition,WHIM syndrome [Hernandez 2003, Kawai 2009]. Two of these CXCR4 variantswere evaluated and the results demonstrated that X4P-001 was able toinhibit SDF-1α-mediated calcium flux in these carboxy-terminal truncatedvariants. These data further indicate that X4P-001 acts via interactionwith the extracellular region of CXCR4. Furthermore it is significantfrom the perspective of X4P-001 as a potential therapeutic option forWHIM syndrome that it can inhibit multiple variants of CXCR4.

Additionally it was shown that X4P-001 is an allosteric inhibitor ofCXCR4 by comparing the dose/response of SDF-1α in the calcium flux assayin the presence of increasing amounts of X4P-001 [Mosi 2012]. Based oninhibition being mediated by non-competitive binding, the extent ofinhibition is therefore dependent solely on the concentration of X4P-001and is independent of the concentration of SDF-1α ligand.

In-Vivo Pharmacology

The primary in vivo pharmacologic effect of X4P-001 is mobilization ofwhite blood cells (WBC) from bone marrow. Three studies are summarizedbelow which demonstrate the mobilization of WBC from the bone marrow ofbeagle dogs and C3W/He J mice.

Hematologic Effects in the Male Beagle Dog

Three fasted male Beagle dogs received a single dose of X4P-001 inaqueous solution by oral gavage at dose levels of 5, 15, and 35 mg/kg (1dog per dose level) in a volume of 1 mL/kg. Blood samples (approximately3 mL each) were obtained at multiple timepoints from each animal bydirect venipuncture of the jugular vein and collected using Vacutainer®tubes containing K3EDTA as the anticoagulant. Blood samples wereobtained at pre-dose, and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 7, 12, and24 hours post-dose. Blood samples were stored at ambient roomtemperature prior to automated differential analysis

Body weights were determined prior to dosing on the day of test articleadministration. Animals were observed at least once daily and at timesof blood sampling.

Hematology parameters included the following:

White Blood Cell Count (WBC)

Differential white blood cell count (absolute and relative)

-   -   Neutrophil    -   Lymphocytes    -   Monocytes    -   Eosinophils    -   Basophils    -   Large Unstained Cells (LUC)    -   Hematocrit (HCT)    -   Hemoglobin (HGB)    -   Mean Corpuscular Hemoglobin (MCH)    -   Mean Corpuscular Hemoglobin Concentration (MCHC)    -   Mean Corpuscular Volume (MCV)    -   Platelet Count (PLT)    -   Red Blood Cell Count (RBC)

Results

The effect of X4P-001 on WBC and absolute neutrophil and lymphocytecounts is shown in FIG. 8. Maximal increases in WBC occurred 4-12 hourspost-dose. Peak elevations ranged from 1.8-2.9-fold above baselinevalues at the 15 and 35 mg/kg dose levels, with somewhat lower(1.5-fold) elevations observed at the 5 mg/kg dose level. Althoughlimited by the small sample size, these results suggest that maximalincreases may have been achieved at the higher dose levels. WBC,neutrophil, and lymphocyte counts remained elevated at the 15 and 35mg/kg dose levels at 24 hours, with evidence of return to baseline. Noother hematological effects were observed.

A 28-Day Oral (Capsule) Study in the Beagle Dog with a 14-Day RecoveryPeriod

A 28-Day GLP oral (capsule) toxicology study was conducted with X4P-001in the male and female beagle dog, and hematology effects were observed,with X4P-001 administered twice-daily (at least 7 hours apart) by oralcapsule for 28 days. A subset of treated animals was evaluated after a14-day recovery period. Table 3 presents the protocol design and Table 4the evaluations schedule.

TABLE 3 Protocol Design for 28-Day Toxicity Study in the Dog AnimalsDose Level Terminal Animals Group (mg/kg/day)^(a) Necropsy 14-dayRecovery 1 0 (empty capsule) 3 M, 3 F 2 M, 2 F 2 10 3 M, 3 F — 3 30 3 M,3 F —

TABLE 4 Protocol Evaluations and Schedules Evaluations Schedule Studyduration Days −10 through Day 42 Treatment Days 1 through 28, twicedaily Clinical Twice daily observation Food Daily consumption Bodyweight Weekly Vital signs^(a) Predose acclimation period; final dosingweek; final recovery week Ophthalmology Predose and during Week 4Electrocardiogram Predose and during Week 4, at ~1 evaluation hourpost-first daily dose Clinical Predose d −10, d −2; Post-dose, DayPathology^(b) 29 (all groups), Day 42 (recovery only) Necropsy^(c) Day29, terminal; Day 42, recovery ^(a)Vital signs comprise heart rate,blood pressure, and body temperature ^(b)Clinical pathology comprisedhematology, coagulation, serum, and urinalysis (done only once predose).^(c)Necropsy studies comprise organ weight, macroscopic, and microscopicobservations, including 500-cell bone marrow differential count.

As shown in Table 5 below, increases in absolute counts for neutrophils,lymphocytes, and monocytes were observed at termination (Day 28); thesewere of greater magnitude and more likely statistically significant infemales. These changes were considered consistent with thepharmacological effects of X4P-001. After the 14-day recovery period(only 100 mg/kg dose group evaluated) all hematology results returned towithin normal levels.

TABLE 5 Hematology Findings at Termination in 28-Day Oral Toxicity Studyin the Dog 10 mg/kg/d 30 mg/kg/d 100 mg/kg/d Observation (3M, 3F) (3M,3F) (3M, 3F) Hematology M incr 1.2x; M incr 1.2x; M incr 1.8x;neutrophils F incr 1.9x† F incr 2.3x† F incr 2.8x† (abs) lymphocytes Mincr 1.3x; M incr 1.6x; M incr 2.3x†; (abs) F incr 1.4x F incr 1.6x† Fincr 1.4x† monocytes (abs) M incr 1.2x; M incr 1.3x; M incr 1.9x†; Fincr 1.6x† F incr 1.9x† F incr 2.4x† reticulocytes No changes No changesF decr 0.24x† Coagulation No changes No changes No changes abs,absolute; †p < 0.05 compared with control animals of the same sex

Hematologic Effects of X4P-001 in Mice

A further study was conducted to determine whether X4P-001 mobilizesprogenitor/stem cells in mice. All experiments were performed in C3W/HeJ mice. X4P-001 and AMD3100/plerixafor were administered via singlesubcutaneous injection at the doses described below. The mobilizationcapacity of X4P-001 was assessed by the numbers ofgranulocyte-macrophage (CFU-GM), erythroid (BFU-E) and multipotential(CFU-GEMM) progenitor cells per mL of blood. The progenitors werestimulated to form colonies in vitro with the combination of 1 U/mL rhuEPO, 50 ng/mL rmu SLF, 5% vol/vol pokeweed mitogen mouse spleen cellconditioned medium (PWMSCM), and 0.1 mM hemin. Plates were scored 7 daysafter incubation at 37° C., 5% CO₂, lowered (5% CO₂) and in a humidifiedchamber.

Results

X4P-001 mobilized progenitors in C3H/HeJ mice following a singlesubcutaneous injection. In the first experiment (data shown in Table 6),mice received a dose of 5 mg/kg- and the number of progenitors in thecirculating blood was measured at various time points (0.25, 0.5, 1, 2,6 and 24 hours). The peak of nucleated cell mobilization occurred atapproximately 1-2 hours post-injection. Peak increases of CFU-GM, BFU-Eand CFU-GEMM were 4.21 (30 min.), 2.49-2.54 (30-60 min.), and 2.58-2.67(30-60 min.)-fold, respectively over control (saline injection).

TABLE 6 X4P-001 Time Course of Progenitor Mobilization AMD11070 TimeCourse (dose = 5 mg/kg) Control @ - 15″ @ - 30″ @ - 60″ @ - 2′ @ - 6′@ - 24′ Nucleated Mean 4.35 5.10 6.14 6.92 8.29 5.66 4.31 CellularitySTD 0.14 1.09 1.20 0.57 0.55 0.28 0.82 (×10⁶/mL) STE 0.08 0.63 0.69 0.330.32 0.16 0.47 PBL-LD Fold Chg 1.00 1.17 1.41 1.59 1.90 1.30 0.99 P1.000 0.307 0.062 0.002 0.000 0.002 0.930 GM Mean 302.3 785.1 1273.8866.0 897.5 387.5 386.3 STD 20.5 180.3 85.4 197.8 165.6 54.6 110.5 STE11.8 104.1 49.3 114.2 95.6 31.5 63.8 Fold Chg 1.00 2.60 4.21 2.86 2.971.28 1.28 P 1.000 0.010 0.000 0.008 0.003 0.065 0.265 BFU Mean 92.5148.8 230.4 235.1 165.3 99.9 84.6 STD 30.9 27.1 70.2 68.2 47.5 17.8 44.4STE 17.8 15.6 40.5 39.4 27.4 10.3 25.7 Fold Chg 1.00 1.61 2.49 2.54 1.791.08 0.92 P 1.000 0.076 0.036 0.030 0.090 0.735 0.814 GEMM Mean 38.665.6 99.6 103.1 68.9 37.6 37.7 STD 10.6 17.6 24.2 20.3 23.7 16.0 20.6STE 6.1 10.2 14.0 11.7 13.7 9.3 11.9 Fold Chg 1.00 1.70 2.58 2.67 1.780.97 0.98 P 1.000 0.085 0.016 0.008 0.114 0.934 0.946 Animals per group= 3, control group = 1, total animals = 21

An X4P-001 dose-response was performed by measurement of the number ofcirculating progenitors in the blood at 1 hour post-injection at variousdoses (1.5, 2.5, 5, 10 and 20 mg/kg). As shown in Table 7, there appearsto be an upper limit to the number of progenitors that can be mobilizedwith X4P-001, exemplified by the fold increases of CFU-GM. The numbersof CFU-GM in the circulating blood dose-dependently increased with peakfold increase of 6.0-7.7 over control at 5-20 mg/kg. Peak fold increasesrespectively of 2.3 and 3.8 for BFU-E and CFU-GEMM were noted at 10mg/kg. At doses below 5 mg/kg X4P-001, the fold-increases in the numbersof BFU-E and CFU-GEMM were not statistically significant.

TABLE 7 Dose Response in C3H/HeJ Mice AMD11070 (mg/kg) Control 20 10 52.5 1.5 Nucleated Mean 6.48 9.62 9.94 7.65 8.29 6.94 Cellularity STD0.69 1.26 4.02 2.74 2.07 0.50 (×10⁶/mL) STE 0.40 0.73 2.32 1.58 1.200.29 PBL-LD Fold Chg 1.00 1.48 1.53 1.18 1.28 1.07 P 1.000 0.019 0.2160.514 0.225 0.406 GM Mean 188.0 1314.2 1444.2 1119.8 626.5 428.0 STD51.8 262.0 939.8 1011.9 220.4 118.7 STE 29.9 151.2 542.6 584.2 127.368.5 Fold Chg 1.0 7.0 7.7 6.0 3.3 2.3 P 1.000 0.002 0.082 0.186 0.0280.033 BFU Mean 114.4 261.4 268.1 181.6 144.8 143.8 STD 5.6 35.8 61.458.6 79.3 47.1 STE 3.2 20.7 35.5 33.8 45.8 27.2 Fold Chg 1.0 2.3 2.3 1.61.3 1.3 P 1.000 0.002 0.012 0.119 0.544 0.343 GEMM Mean 58.4 145.0 224.4141.0 78.3 53.3 STD 45.5 50.5 60.7 34.4 8.1 8.9 STE 26.3 29.2 35.0 19.84.7 5.1 Fold Chg 1.0 2.5 3.8 2.4 1.3 0.9 P 1.000 0.092 0.019 0.066 0.4980.857 Animals per group = 3, control group 1, total animals = 18

A final experiment was performed to compare the progenitor cellmobilization capacity of X4P-001 and AMD3100/plerixafor. Both drugs wereadministered subcutaneously at a dose of 5 mg/kg, and the number ofprogenitors in the circulating blood were measured for AMD3100 at asingle 1 hour time point (the peak of mobilization with AMD3100, datanot shown) versus X4P-001 at 0.25, 0.5, 1 and 2 hours post-injection. Asshown in Table 8 comparing the fold-increase in CFU-GM, BFU-E, andCFU-GEMM, AMD3100 caused respective maximum increases of 9.11, 3.12, and4.35, whereas respective peaks of mobilization with X4P-001 were 3.56,2.84 and 3.21.

TABLE 8 X4P-001 Time Course Compared to ADM3100/Plerixafor (Dose 5mg/kg) AMD3100 AMD11070 Control @ - 60″ @ - 15″ @- 30″ @ - 60″ @ - 2′Nucleated Mean 6.23 10.08 8.04 8.28 7.34 9.71 Cellularity STD 2.16 2.131.30 0.94 0.69 1.29 (×10⁶/mL) STE 1.25 1.23 0.75 0.54 0.40 0.74 PBL-LDFold Chg 1.00 1.62 1.29 1.33 1.18 1.56 P 1.000 0.092 0.281 0.205 0.4440.074 GM Mean 214.1 1950.3 588.3 705.9 761.4 619.6 STD 118.2 566.4 168.1151.5 239.2 158.7 STE 68.2 327.0 97.1 87.5 138.1 91.6 Fold Chg 1.00 9.112.75 3.30 3.56 2.89 P 1.000 0.007 0.034 0.011 0.024 0.024 BFU Mean 66.5207.7 188.9 151.9 144.3 108.5 STD 39.6 35.4 55.0 23.8 47.5 43.0 STE 22.920.4 31.7 13.8 27.4 24.8 Fold Chg 1.00 3.12 2.84 2.29 2.17 1.63 P 1.0000.010 0.035 0.033 0.095 0.281 GEMM Mean 31.8 138.5 93.8 79.0 102.2 62.4STD 2.6 18.1 21.1 34.5 50.5 34.9 STE 1.5 10.5 12.2 19.9 29.1 20.1 FoldChg 1.00 4.35 2.95 2.48 3.21 1.96 P 1.000 0.001 0.007 0.078 0.074 0.205Animals per group = 3, control group = 1, total animals =18Conclusions from In Vivo Studies

Single oral doses of X4P-001 at 5, 15, and 35 mg/kg in beagle dogsresulted in increased levels of total circulating WBC, neutrophils, andlymphocytes. The increases were consistently apparent at 4 hours andtypically peaked at 12 hour, occasionally earlier. At 5 mg/kg, all threecell counts increased to 1.47× baseline. At 15 mg/kg, neutrophilsincreased to 1.8× and lymphocytes to 2.9×; and at 35 mg/kg, neutrophilsto 2.7× and lymphocytes to 1.9×.

In multiple-dose toxicity studies in dogs, hematological effects after28 days were qualitatively and quantitatively consistent with thefindings in the single dose study in beagle dogs.

In C3H/HeJ mice, X4P-001 dose-dependently increased the number ofcirculating progenitors up to a dose of 5-10 mg/kg s.c.

Example 2: Clinical: Patients to be Treated

Patients who may be treated according to the present invention includepatients who have been diagnosed with WHIMS or with MKX; and patientswho present the characteristic mutations in their CXCR4 gene. Otherpatients who may benefit from the present invention may includeindividuals presenting with the following screening criteria:

Neutropenia (ANC≤400 or ≤600/μL) and/or lymphopenia (ALC≤650 or≤1000/μL)—the latter is not characteristic of other chronicneutropenias;

Neutropenia and chronic warts;

Myelokathexis on bone marrow aspirate;

Patients meeting the above criteria are genetically screened for MKX.Patients with the characteristic mutations in CXCR4 are the most likelyto benefit from treatment in accordance with the present invention.

Thus, the effects of X4P-001 is expected to be greatest in patients withmyelokathexis associated with mutation in CXCR4. In addition, patientswho may benefit from treatment according to the present inventioninclude individuals presenting with the following screening criteria:

-   -   1. Has a genotype-confirmed CXCR4 mutation consistent with WHIM        syndrome; and    -   2. Has ANC≤400 or ≤600/μL, or ALC≤650 or ≤1000/μL, or both, on        at least two independent blood samples collected over a period        of up to 14 days.    -   3. Have one of the following findings:        -   A bone marrow aspirate or biopsy showing myelokathexis        -   Peripheral WBC counts (≥2 independent samples, obtained in            the absence of signs or symptoms of acute infection, and            when not having received G- or GM-CSF in the past 7 days)            showing absolute neutrophil count <900/μL and/or absolute            lymphocyte count <1,500/μL.

Examples of candidate endpoints based on 6 months on-treatment comparedto the prior 6 months without treatment include:

-   -   50% reduction in hospitalizations    -   50% reduction in infections requiring courses of systemic        antibiotics    -   50% reduction in area involving cutaneous warts    -   sustained increases in circulating neutrophils (e.g.,        ANC>600/μL; ANC>800/μL; ANC>1000/μL; or ANC>1,200/μL on at least        85% of assessments)    -   sustained increases in circulating lymphocytes (e.g.,        ALC>1000/μL; ALC>1,200/μL; or ALC>1,500/μL on at least 85% of        assessments)    -   Achieve pre-defined levels of protective antibody in response to        at least 2 approved vaccines previously administered without        achieving that level.    -   50% reduction in days of work or school missed due to infection    -   sustained increases in circulating neutrophils.

Not all endpoints are applicable to all patients, just as all patientswith WHIM do not exhibit identical clinical manifestations. However, allpatients exhibit at least one clinical and one laboratory metric.

Patients are preferably initiated on treatment orally with X4P-001 25 mgonce daily, 25 mg twice daily, or 50 mg once daily. Provision is madefor dose reduction (which can be via increased interval; e.g., to everyother day or twice weekly) in the event of toxicity or dose increase(e.g., to >50 mg once daily or higher daily dosage, such as 100 mg/dayor 150 mg/day) in the event of an inadequate response.

An exemplary initial dosage is via X4P-001 25 mg capsules, administeredorally in the morning in a fasted state, with no food or drink (exceptwater) after midnight and continuing until 2 hr post-dose. In twicedaily dosage regimens, capsules are preferably administered orallytwelve hours apart.

Example 3: Clinical Treatment Regimens

Dosing Regimen for Patients with WHIM Syndrome:

X4P-001 at a determined dose of 25 mg or 50 mg daily is administeredorally. Patients are instructed about both dosing schedule andrequirements relating to food or drink near the time of dosing.

Dosing Schedule.

The first daily dose is taken in the morning. For twice daily dosing,doses should be taken twelve hours apart. Dosing should be at the sametimes each day±2 hr.

Restrictions relating to food. Absorption is impacted by food andpatients will be instructed as follows:

For the morning dose:

-   -   No food or drink (except water) after midnight until the time of        dosing    -   No food or drink (except water) for 2 hour after dosing.

Dosing of X4P-001 may be adjusted by the clinician as appropriate. Thedose of X4P-001 may be lowered according to the judgment of theclinician. If a patient receiving X4P-001 experiences an adverse eventat Grade >2, the dose of X4P-001 may be lowered according to thejudgment of the clinician. If a patient successfully completes the first2 to 4 weeks of treatment, that is, without experiencing any adverseevents greater than Grade 2, the daily dose of X4P-001 may be increasedconsistent with the judgment of the clinician.

Alternative Dosing Regimens for Patients with WHIM Syndrome

Patients' initial absolute neutrophil count (ANC) (neutropenia) (ANC<400or <600/μL) and/or absolute lymphocyte count (ALC) (lymphopenia)(ALC<650 or <1000/μL)] are measured. [Note—the latter is notcharacteristic of other chronic neutropenias]. If the patient exhibitsANC below 400 or below 600/μL; and/or ALC remains below 650 or below1000/μL, then treatment with X4P-001 is initiated. Patients areinitiated on treatment with X4P-001 25 mg orally once daily, 25 mgorally twice daily, or 50 mg orally once daily. Provision is made fordose reduction (which can be via increased interval, e.g., to everyother day or twice weekly) or halt of administration in the event oftoxicity, or dose increase (e.g., to >50 mg daily or higher dailydosage) in the event of an inadequate response.

ANC and ALC are monitored monthly or, preferably, bi-weekly. If ANC>400or >600/μL; and/or ALC>650 or >1000/μL is achieved, the patient willcontinue on the original daily dosage regimen. If ANC remains below 400or below 600/μL; and/or ALC remains below 650 or below 1000/μL, and thepatient exhibits no severe adverse effects, the patient's dose will beincreased to by 25 mg or 50 mg daily [or by 25 mg orally twice daily; 12hours apart].

Patients on the increased dose of 50 mg/μL per day will continue to bemonitored monthly or, preferably, bi-weekly. If ANC≥400 or ≥600/μL;ALC≥650 or ≥1000/μL is achieved (without severe adverse effects), thepatient will continue on the increased dosage regimen. If ANC remainsbelow 400 or below 600/μL; and/or ALC remains below 650 or below1000/μL, (and patient exhibits no severe adverse effects), the patient'sdose will be further increased to by an additional 25 mg or 50 mg daily.

The above procedures of increasing daily dosage regimens may be repeateduntil the patient achieves ANC≥400 or ≥600/μL; and/or ALC≥650 or≥1000/μL (without severe adverse effects); or until the patient is beingtreated at a maximum tolerated daily dose.

Alternatively, ANC and ALC are analyzed as area-under-the-curve (AUC)relative to pre-specified clinically meaningful thresholds of 400 or600/μL and 650 or 1000/μL, respectively. The 24-hour AUC will becalculated using the trapezoidal method with area above threshold beingpositive, and area below threshold, negative. Patients withAUC_(ANC)<2000 cell·hr/μL or AUC_(ALC)<5000 cell·hr/μL at monthly orbi-weekly evaluations will have X4P-001 daily dose increased in 25 mg or50 mg increments up to a maximum dose of 150 mg QD. Because ANC and ALCin WHIM patients are significantly impacted by acute infection, alone orwith antibiotic, G-CSF or IVIG treatment, monitoring of AUC should bedelayed or discontinued in patients with acute infection, until suchpatient has remained afebrile for at least 2 weeks.

If the patient experiences adverse effects at any time, provision ismade for dose reduction (i.e., lower dosage and/or increased intervalbetween administrations drug), or administration is halted.Additionally, the treating physician may use his or her professionaljudgment and discretion in determining the starting dose, and how bestto titrate to the appropriate dose of X4P-001 for any individualpatient.

An exemplary composition of a X4P-001 25 mg capsule that may be used isshown in Table 9 below.

TABLE 9 Quantitative Composition of Exemplary X4P-001 25 mg CapsuleReference Quantity Component to Standard Function (mg/capsule) % w/wX4P-001 In House Active 25.0 14.7 Ingredient Microcrystalline NF Diluent132.7 78.1 Cellulose Croscarmellose NF Disintegrant 10.2 6.0 SodiumSodium Stearyl NF Lubricant 1.7 1.0 Fumarate Colloidal Silicon USP FlowAid 0.4 0.2 Dioxide Sum Total 170.0 100.0 Hard Gelatin USP Packaging NANA Capsules, Size 1

Example 4: Assessments of Treatment Effect

Circulating White Blood Cells

Whole blood samples are analyzed for:

CBC and absolute leukocyte differential counts by standard laboratorymethods, including WBC counts, including absolute numbers oflymphocytes, neutrophils, and CD34+ cells. The number and percentage ofpatients achieving ANC>1,500/μL; ALC>900/μL. The absolute increase inblood neutrophil counts from pre-treatment baseline for each subject,including at the maximum observed in the hours post-dosing; and themaximum observed pre-dose on stable drug administration regimen. Theseresults are compared with data from healthy adults administered X4P-001.

Peripheral Blood Mononuclear Cells (PBMC) subpopulations by flowcytometry are shown below in Table 10.

TABLE 10 Candidate Subsets of Circulating Lymphocytes and Monocytes CD4+T cells CD3− CD56+ (NK cells) CD34+ (stem cells) CD4+ CD45RA+ CD19+ (Bcells) CD49f+ (stem cells) (naïve T cells) CD19+ CD27− IgM+ CD90+ (stemcells) CD4+ CD45RA− (transitional B cells) (memory T cells) CD14+(monocytes) CD8+ T cells CD14+ CD16− CD8+ CD45RA+ (classical monocytes)(naïve T cells) CD14+ CD16+ CD8+ CD45RA− (inflammatory monocytes)(memory T cells)

Immunoglobulins and Specific Antibodies

Serum samples are analyzed for levels of total IgG, IgG subclasses, IgA,and IgM, and levels of selected specific antibodies to common vaccineantigens (Table 11).

TABLE 11 Common Vaccines Which Elicit Protective Antibody by Age RangeInitially Administered Birth to 6 years (bacteria) Birth to 6 years(viruses) Age 7 to 18 years Diphtheria toxoid Measles, RubellaMeningococcal Tetanus toxoid Varicella Polio polysaccharide H.influenzae type B (inactivated vaccine) Human papilloma polysaccharideHepatitis B, Hepatitis A virus Pneumococcal polysaccharides

The following parameters are reviewed:

-   -   Increases in levels of IgG, IgA, and IgM

For patients with sub-protective titers of specific antibody to approvedmicrobial vaccines, the clinician and patient may decide uponrevaccination, and analyze for development of protective titerspost-vaccination.

Bone Marrow Aspirates

Bone marrow aspirates are obtained from consenting patients atscreening, after 4 and after 20 weeks of treatment. Aspirates arereviewed by a blinded hematopathologist and graded for cellularity andmyelokathexis. If sufficient material is available, samples are analyzedfor markers of neutrophil apoptosis and lymphocyte subpopulations.

The following parameters are reviewed:

-   -   Decrease in hypercellularity    -   Decrease in fraction of apoptotic WBC

Clinical Assessments

Warts.

Warts are monitored by photographs and/or recording of lesion location,number, and size.

Infections.

Temperatures are taken twice daily, signs or symptoms of infections,resulting in fever, prompting physician visits, requiring antibiotics,or associated with hospitalization, are reviewed and compared with theyear prior to treatment.

Pharmacokinetic Assessments

If desired, pharmacokinetic assessment of blood samples for plasmalevels of X4P-001 may be conducted. Blood samples are collected asscheduled. Samples are analyzed for X4P-001 concentration usingreversed-phase high performance liquid chromatography (RP-HPLC) withMS/MS detection. The validated range of this bioanalytic method is 30 to3,000 ng/mL in plasma.

Pharmacokinetics (PK) and Pharmacodynamics (PD).

In order to evaluate the pharmacokinetic properties of therapy withX4P-001, levels of X4P-001, PK samples are obtained on all patients inPart A as follows

-   -   Day 1: pre-dose; post-dose at 30, 60, 90 min (each ±10%) and 2,        3, 4 hr (each ±15 min)    -   Week 5 visit: pre-dose; post-dose at 30, 60, 90 min (each ±10%)        and 2, 3, 4, 8 hr (each ±15 min)    -   Week 9 and Week 13 visits: pre-dose.

Visits are scheduled for early in the day and patients are instructed toarrive at the clinic fasting and having not taken their morning dose ofX4P-001.

PK are analyzed by patient and dosage regimen over the preceding weekusing descriptive statistics for AUC, Cmax, and Cmin.

If results suggest either (a) ongoing accumulation beyond Week 5 or (b)a specific PK parameter is associated with adverse effects, thenadditional sampling days may be added.

PD samples are collected on Day 1 and at Week 5 visit concurrent withscheduled PK samples (see above) for:

-   -   Total white blood cell (WBC) counts    -   Counts of circulating CD34+ positive cells    -   Assessments may include samples analyzed by flow cytometry for        subpopulations of PBMCs.

If sample yields permit, additional investigational immunomodulatorysubsets may be analyzed (See Table 11).

Of course, the treating physician may apply his or her professionaljudgment and discretion and any established standards of care, whatparameters of assessment (e.g., the desired levels of ANC and ALC)should be used in determining the treatment regimen for any individualpatient.

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Study Reports

-   A 28 day Oral (Capsule) Toxicity Study in the Male and Female Beagle    Dog with a 14 day Recovery (Study CTBR77401): November 2003.-   Pharmacology & Toxicology of AMD11070: Hematological Effects in the    Male Beagle Dog. AnorMED, Inc. Mach 18, 2003 (Study No. AOM0031).-   Hematological Effects of AMD11070 in Mice. Indiana University School    of Medicine. Mar. 14, 2003 (Study No. AOM0033).-   ACTG (DIAIDS) Protocol A5210. Unpublished data.

Internet References

-   George Diaz, Virginia Gulino. Whim syndrome. Orphanet Encyclopedia.    June 2004; http://www.orpha.net/data/patho/GB/uk-Whim.pdf-   NORD (National Organization for Rare Diseases) 2015:    https://rarediseases.org/rare-diseases/whim-syndrome-   Office of Rare Diseases:    https://rarediseases.info.nih.gov/gard/9297/whim-syndrome/resources/1-   Orphanet, WHIM Syndrome:    http://www.orpha.net/consor/www/cgi-bin/OC_Exp.php?lng=EN&Expert=51636    Last Update October 2014-   US Census Bureau:    http://www.census.gov/quickfacts/table/PST045214/00 Last Revised    June 2015

We claim: 1-20. (canceled)
 21. A method for treating WHIM syndrome in apatient in need thereof, comprising administering to the patient about200 mg, about 250 mg, about 300 mg, about 400 mg, about 450 mg, about500 mg, or about 600 mg of X4P-001 or a pharmaceutically acceptable saltor composition thereof per day in a single or divided dose.
 22. Themethod of claim 21, wherein the X4P-001 or a pharmaceutically acceptablesalt thereof is administered in a dose of about 400 mg per day in asingle or divided dose.
 23. The method of claim 21, wherein the patientexhibits warts.
 24. The method of claim 21, wherein cells taken from thepatient exhibit expression of a mutant form of CXCR4.
 25. The method ofclaim 21, wherein cells taken from the patient exhibit increasedexpression of CXCR4.
 26. The method of claim 21, further comprising thestep of obtaining a biological sample from the patient and measuring theamount of a disease-related biomarker.
 27. The method of claim 26,wherein the biological sample is a blood sample.
 28. The method of claim27, wherein the disease-related biomarker is circulating CXCR4,SDF-1α/CXCL12, or GRK3 (G protein coupled receptor kinase 3).
 29. Themethod of claim 22, wherein the X4P-001 or a pharmaceutically acceptablesalt or composition thereof is administered orally once per day.
 30. Themethod of claim 22, wherein the X4P-001 or a pharmaceutically acceptablesalt or composition thereof is administered orally twice per day. 31.The method of claim 29, wherein the patient is in a fasted state whenthe X4P-001 or a pharmaceutically acceptable salt thereof isadministered.
 32. The method of claim 22, wherein the patient originallyexhibited ANC less than 600/μL and/or ALC less than 1000/μL beforetreatment with X4P-001 or a pharmaceutically acceptable salt thereof.33. The method of claim 22, wherein the patient originally exhibited ANCless than 400/μL before treatment with X4P-001 or a pharmaceuticallyacceptable salt thereof on at least two independent blood samplescollected over a period of up to 14 days.
 34. The method of claim 22,wherein the patient originally exhibited ANC less than 400/μL and/or ALCless than 650/μL before treatment with X4P-001 or a pharmaceuticallyacceptable salt thereof on at least two independent blood samplescollected over a period of up to 14 days.
 35. The method of claim 33,wherein the method results in increases in ANC levels to at least about600/μL on at least 85% of assessments.
 36. The method of claim 33,wherein the method results in increases in ALC to at least about 1000/μLon at least 85% of assessments.
 37. The method of claim 33, wherein themethod results in improved levels of protective antibody in the patientin response to a vaccine.
 38. The method of claim 33, wherein the methodresults in at least 50% less respiratory tract infections.
 39. Themethod of claim 33, wherein the method results in increased levels oftotal circulating WBC, neutrophils, and/or lymphocytes to at least 1.4×baseline.